Pass a DataTime parameter to stored procedure and check a condition - sql-server

Question

assumption:
I need to sync a 'PublicDB' from a 'PrivateDB' database. Where two parameters should pass to stored procedure, server name and a datetime type parameter.
HistoryDate is not primary key but use for updating.
Scenario:
If today is 8th and user do not select any previous date from dateTimePicker -UI- this stored procedure only will update records on 8th.
If today is 8th and user select 5th of month= targetdate in my SP, it should delete 'PublicDB' table from 4th then insert 5th, 6th and 8th again.
Problem:
server parameter works fine but for datatime parameter:
If Sp execute in sql server get this error:
Conversion failed when converting date and/or time from character string.
if added to table Adapter it got this error:
Generated SELECT statement
Conversation failed when converting date / or time from character string.
*To apply these settings to your query click finish*
here is the sp:
CREATE PROCEDURE [dbo].[spname] #Server SYSNAME,
#TDate NVARCHAR(50) --have tested: DateTime
AS
BEGIN
DECLARE #SQL1 NVARCHAR(2000);
DECLARE #SQL2 NVARCHAR(2000);
DECLARE #LastRecordDate DATETIME;
DECLARE #Count INT;
DECLARE #TargetDate DATETIME;
SET #TargetDate = CONVERT(DATETIME, #TDate, 121);
SET #Count = CONVERT(INT, 'SELECT COUNT(*) FROM [' + #Server + '].[PublicDB].[dbo].[TableName]
WHERE HistoryDate >= [' + #TargetDate + '] ');
EXECUTE sp_executesql #Count;
IF #Count > 0 BEGIN
SET #SQL1 = 'DELETE FROM [' + #Server + '].[PublicDB].[dbo].[TableName]
WHERE HistoryDate >= [' + #TargetDate + ']
INSERT INTO [PublicDB].[dbo].[TableName]
SELECT TOP 5
[HistoryDate]
,[columnName1]
,[columnName2]
,[columnName3]
,[columnName4]
,[columnName5]
,[columnName6]
FROM PrivateDB.dbo.TableName
WHERE HistoryDate >= [' + #TargetDate + ']
';
EXECUTE sp_executesql #SQL1;
END
ELSE BEGIN
SET #LastRecordDate = CONVERT(DATETIME, 'SELECT TOP 1 HistoryDate FROM [PublicDB].[dbo].[TableName] ORDER BY HistoryDate DESC', 121);
-- has tested: cast('SELECT TOP 1 HistoryDate FROM [Public].[dbo].[TableName] ORDER BY HistoryDate DESC' as datetime)
EXECUTE sp_executesql #LastRecordDate;
SET #SQL2 = '
INSERT INTO [' + #Server + '].[PublicDB].[dbo].[TableName]
SELECT TOP 5
[HistoryDate]
,[columnName1]
,[columnName2]
,[columnName3]
,[columnName4]
,[columnName5]
,[columnName6]
FROM PrivateDB.dbo.TableName
WHERE HistoryDate > [' + #LastRecordDate + ']
';
EXECUTE sp_executesql #SQL2;
END
END

Answer 1

I think these lines could be the problem
SET #Count = CONVERT(INT, 'SELECT COUNT(*) FROM [' + #Server + '].[PublicDB].[dbo].[TableName]
WHERE HistoryDate >= [' + #TargetDate + '] ');
You are asking to convert a string / datetime to an int
I guess that you are trying to get a count from the select statement, one way would be something like the following (not tested!)
CREATE TABLE #t_count(no int)
DECLARE #sqlcount varchar(1000)
DECLARE #count int
SET #sqlcount = 'INSERT into #t_count SELECT COUNT(*)
FROM [' + #Server + '].[PublicDB].[dbo].[TableName]
WHERE HistoryDate >=''' + convert(varchar(30),#TargetDate,120) + ''''
EXEC( #sqlcount )
SELECT #count = no FROM #t_count
example sqlfiddle
EDIT
I see you updated your answer a little http://sqlfiddle.com/#!2/d41d8/14528
but if you read the answer above, you will see that it
creates a temp table
CREATE TABLE #t_count(no int)
builds an sql string to insert the count into the temp table
SET #sqlcount = 'INSERT into #t_count SELECT COUNT(*)
FROM [' + #Server + '].[PublicDB].[dbo].[TableName]
WHERE HistoryDate >=''' + convert(varchar(30),#TargetDate,120) + ''''
EXEC( #sqlcount )
gets the count value from the table
SELECT #count = no FROM #t_count
Your edit does not do this!
Also you are enclosing literal values in [] for some reason these need removed
good
where historydate = '2012-12-12 12:12'
bad
where historydate = [2012-12-12 12:12]